Ointment foil and method of preparing the same

ABSTRACT

OINTMENT FOILS FOR APPLICATION TO THE INJURED OR INTACT SKIN ARE PREPARED BY DRYING AN OIL-IN-WATER TYPE EMUL: SION OF CONVENTIONAL IONTMENT INGREDIENTS AT ELEVATED TEMPERATURE TO A WATER CONTENT OF 1% TO 15%, THE FOILS SO OBTAINED ARE FIRM ENOUGH TO BE HANDLED WITHOUT A SUPPORT OR CARRIER, YET FLEXIBLE ENOUGH TO CONFORM TO THE CONTOURS OF THE BODY.

United States Patent O 3,803,300 OINTMENT FOIL AND METHOD OF PREPARINTHE SAME Heinz Pospischil, Oskar-Orth-Str. 22, D-665 Homburg, Saar,Germany No Drawing. Filed Mar. 5, 1971, Ser. No. 121,555 Claimspriority, application Germany, Mar. 18, 1970,

P 20 12 775.7 Int. Cl. A45d 40/26; A61f 13/00; A61m 35/00 US. Cl. 424-284 Claims ABSTRACT OF THE DISCLOSURE Ointment foils for application tothe injured or intact skin are prepared by drying an oil-in-water typeemulsion of conventional ointment ingredients atrelevated temperature toa water content of 1% to The foils so obtained are firm enough to behandled without asupport or carrier, yet flexible enough to conform tothe contours of the body.

This invention relates to shaped ointment bodies and to a method ofpreparing the same.

It is common practice to apply to the skin ointments containingtherapeutically or cosmetically active agents. The ointments have theconsistency of a very soft solid barely capable of maintaining its shapeunder the forces of gravity or even softer. They are either applieddirectly to the skin from a container, or they are applied to anabsorbent carrier such as a fabric on an industrial scale and appliedwhile supported on the carrier.

The ointments employed in the last-described manner must be practicallyfree from water and have a continuous oily or fatty phase consisting ofpetroleum jelly, polyethylene glycol or the like because conventionalointments which are of the oil-in-water emulsion water'type The ointmentbodies of the invention are foil-shaped in accordance with their normalapplications and are emulsions of the oil-in-water type, that is,-theyhave a fat or oil phase colloidally dispersed in a continuous aqueousphase although their water content may be as low as 1% and should not behigher than 15% by weight.

The components of the foil-shaped bodies other than water areconventional ointment ingredients, such as a pharmaceutically acceptableoily or fatty ointment base in an amount of to 60%, 2% to 12% of anemulsifier capable of emulsifying the base. in Water, 3% to 20% of afilm forming agent, 12% to 40%bof a humectant, and 1% to 15 of an activeagent of any type conventionally employed in ointments for therapeuticor cosmetic purposes and compatible with the other ingredients.

. As is frequently desirable in ointments, the oil-in-water.

emulsions of the invention may contain enough titanium oxide or zincoxide to make them opaque. Synthetic surfactants are the preferredemulsifying agents, and may be of the anionic, cationic, or non-ionictypes, numerous such agents being in current pharmaceutical use. Methylcellulose, carboxyrnethyl cellulose, and other cellulose Patented Apr.9, 1974 derivatives capable of dissolving or of swelling in water, andalginates are the preferred film forming agents.

Because of their low Water content, the foil-shaped ointment bodies ofthe invention are shape retaining and may be applied manually to theintact or injured skin without the fingers touching the latter andwithout requiring transfer of the-ointment to gauze or other fabricbefore application to the skin. Yet, they are flexible enough to conformto the substrate under minimal pressure. Large skin areas can quicklyand conveniently be covered.

The foil-shaped ointment bodies of the invention are prepared fromoil-in-water emulsions of higher water content having a paste-likeconsistency by partial evaporation of the original water content when anexposed layer'of the starting emulsion spread on a solid substrate issupplied with thermal energy. The thermal energy is preferably suppliedat a rate to keep the temperature of the initially paste-like layer at50 to C. the actual drying temperature depending on the ingredientsused, and the layer being exposed to a vacuum while being supplied withthermal energy at the lowest temperatures of the preferred range.

The oily or fatty phase of the emulsion may consist of any of the usual,pharmaceutically accepted ointment bases such as mineral oil, ozokerite,petroleum jelly, paraflin, fatty alcohols, vegetable oils and theirhydrogenation products, fatty acid glycerides, and the like. Theemulsifiers suitable for the purpose of the invention include; but areby no means limited to sodium cetostearyl sulfate, 'ethoxylated fattyalcohols, complex emulsifiers such as polyoxyethyleneglycols orpropyleneglycol.

The therapeutically or cosmetically active agents ,are compounded withthe initial emulsion and may include all therapeutic or cosmeticingredients conventionally incorporated in oil-in-water ointments suchas p-chloro-mcresol, hydroxyquinoline and other disinfectants, antibiotica, sulfonamides ,hexachlorophene, acridine dyes, phydroxybenzoicacid esters, quaternary ammonium compounds such as benzalkonium'chloride, cetylpyridinium chloride. Other active agents compatible withthe necessary ingredients of ointment bodies of the invention includetanning agents, allantoin, urea, azulene, various plant'extracts,cortisone derivatives, vitamins, and hormones.

Film forming agents which have been used successfully in the foil-shapedbodies of the invention include polymers having repeating carboxyvinylgroups, methyl cellulose, carboxymethyl cellulose and other watersoluble cellulose derivatives, vegetable mucilage, alginates,'polyvinylpyrrolidone, copolymers of vinyl pyrrolidone and vinyl acetate, agar,carragheen, dextran, and the like.

The initially prepared emulsion is adjusted with water or aqueousethanol to the consistency of a thin, freeflowing paste. A layer of thepaste is spread on a solid substrate of sheet metal, glass, or the likeby means of a knife blade, roller, or other coating apparatus and heatedto'reduce the residual moisture content'to 1% to 15%. Internally heateddrums having a cylindrical surface of polyethylene,polytetrafluoroehtylene, ceramic enamel or glass permit convenientseparation of the dried foil from the heated surface.

When water is evaporated from the emulsion layer at atmosphericpressure, best results are usually obtained at a temperature of thesubstrate between 65 and 110 C. When a lower temperature is needed, theevaporation of the water may be hastened by applying a vacuum. Theinitial thickness of the emulsion layer is chosen to make the dried foil0.2 mm. to 2 mm.'thick.

Alternatively, the starting emulsion may be compounded with relativelylittle water to give it the consistency of a heavy paste which isfurther dehydrated by stirring in an evacuated kettle until the paste isas thick as dough. This heavy paste is then rolled to the desiredthickness and dried to the ultimate water content on heated metal sheetsor a heated rotating cylinder.

The foil-shaped bodies of the invention are readily smoothed on the skinso as to make contact over their entire surface. They readily absorbmoisture discharged from the skin or blood, and effectively releasetheir active agents to the skin through the large interface. While afabric carrier is not usually required for applying foil shaped ointmentbodies of the invention which have dimensions of length and width ofseveral inches, such carriers may be combined with these foil bodies inany desired manner.

Whether or not a layer of fabric is carried by the foil-shaped bodies,they are preferably sealed in a moisture impervious envelope forstorage.

The following examples are further illustrative of the invention, and itwill be understood that the invention is not limited thereto. All partsand percentage figures are by weight.

EXAMPLE 1 3 parts petroleum jelly, parts cetostearyl alcohol (a 1:1mixture of cetyl alcohol and stearyl alcohol), and 1 part of acommercial nonionic surfactant (ethoxylated oleyl alcohol containing5-10 mole percent ethylene oxide and having a hydroxyl number between 80and 110) were heated with stirring until a homogeneous melt wasobtained. An aqueous mixture was prepared at 70 C. from 2 partslow-viscosity methyl cellulose, 1 part polyvinylpyrrolidone, 6 partsglycerin, 1 part panthenol, 1 part allantoin, 0.1 part benzalkoniumchloride, and 80 parts water.

The aqueous and fatty components were combined in in oi1-in-wateremulsion by means of a high speed agitator. The emulsion so obtained wasground with 3 parts zinc oxide, the paste-like mass was applied to apolytetrafiuoroethylene-covered steel sheet in a thickness of 2 mm., andthe metal sheet was heated to maintain a temperature of 100 C. in thepaste layer until the moisture content of the latter had been reduced toabout 3 to 4%. The dried film was flexible but sufiicientlyshape-retaining to be stripped from the substrate and handled withoutdifficulty.

It was used successfully in mitigating symptoms of U lcus cruris.

EXAMPLE 2 An emulsion was prepared as in Example 1 from an oil phaseconsisting of 0.2 part paraffin oil, 3 parts ozokerite, 3 partspetroleum jelly, and 5 parts of a :1 surfactant mixture of cetostearylalcohol and sodium cetylstearyl sulfate, the last-mentioned ingredientbeing a mixture of equal parts of sodium cetyl sulfate and sodiumstearyl sulfate, and cetostearyl alcohol being a corresponding mixtureof the alcohols. The aqueous phase 4 EXAMPLE 3 A fatty phase of anemulsion was prepared from 6 parts petroleum jelly, 10 partscetylstearyl alcohol, 1 part stearic acid, and 2 partspolyoxyethylenesorbitan monooleate by melting and dispersed in anaqueous phase prepared at 70 C. from 4 parts methyl cellulose, 10 partsglycerin, 1 part allantoin, and parts water. The emulsion so preparedwas further blended with 0.5 part neomycin sulfate and 0.05 part vitaminE acetate.

An emulsion layer 3 mm. thick was spread on a metal sheet, and the sheetWas placed in a vacuum furnace kept at a temperature of about 50 C.until the residual moisture in the emulsion was reduced to about 5%.

The product was useful as a general purpose ointment for sore skin.

EXAMPLE 4 A similar, but more viscous emulsion was prepared from amolten oil phase consisting of 3.3 parts petroleum jelly, 6.4 parts ofthe nonionic surfactant of Example 1, 0.5 part polyethyleneglycol (400)stearate, 0.] part butyl p-hydroxybenzoate, and 0.2 part wool fat (adepslanae), and an aqueous phase consisting of 2.2 parts carboxymethylcellulose, 1.2 parts polyvinylpyrrolidone, 5 parts polyethyleneglycol400, 3 parts urea, and 60 parts water of 70 C.

The mass so obtained was partly evaporated in a vacuum kettle withcontinuous stirring until it had the consistency of a stilf paste ordough. This product was placed on sheets in thin layers and dried to aresidual moisture content of 5% at C.

It provided a suitable base for medicinal ointments.

EXAMPLE 5 An emulsion as initially prepared in Example 1 was placed overa layer of surgical gauze spread on metal sheets, whereby the emulsionpenetrated into the fabric. The thickness of the applied emulsion layerwas about 3 mm. prior to subsequent heating to 100 C., whereby theultimate moisture content was reduced to about 34%.

While the invention has been described with reference to specificexamples for the purpose of the disclosure, it should be understood thatit is not limited thereto, but may be practiced, within the scope of theappended claims, otherwise than as specifically described.

What is claimed is:

1. A foil-shaped flexible dried film ointment body of sufficientstrength to be handled While unsupported, and applied manually to theintact or injured skin without the fingers touching the latter, yetflexible enough to conform to the contours of the body, being 0.2 mm. to2 mm. thick, said body essentially consisting of (a) 1% to 15% water;

(b) 20% to 60% of a pharmacologically acceptable oily or fatty ointmentbase selected from the group consisting of mineral oil, ozokerite,petroleum jelly, paraffin, fatty alcohol, wool fat, vegetable oil,bydrogenated vegetable oil, and fatty acid glycerides other than saidvegetable oil or hydrogenated vegetable oil;

(c) 2% to 12% of an emulsifier keeping said base colloidally dispersedin said Water;

(d) 3% to 20% of a film forming agent selected from the group consistingof a polymer having repeating carboxyvinyl groups, methyl cellulose,carboxymethyl-cellulose, alginate, agar, polyvinylpyrrolidone,carragheen, and dextran;

(e) 1% to 40% of a humectant;

(f) 1% to 15% of a therapeutically active agent compatible with saidbase, said emulsifier, said film forming agent, said humectant, and saidwater,

(3) said active agent being a disinfectant, an antibiotic, asulfonamide, a tanning agent, allantoin, urea, azulene, a plant extract,a cortisone derivative, or a vitamin,

(2) all percentage values being by weight of said bod 4. A body as setforth in claim 1, wherein said emulsifier is sodium cetylstearylsulfate, ethoxylated fatty alcohol, polyoxyethylenesorbitan fatty acidester, soap, or a cationic surfactant.

References Cited UNITED STATES PATENTS 259,268 6/ 1882 Buczkowski 424-28X 1,687,643 10/1928 Berliner 424-28 X 1,836,833 12/1931 Amos 424-28 X1,353,954 9/1920 Henry 424-28 X Washburn 424-28 X Wheeler 424-28 XWilliams 206-46 Duane et a1. 15-506 Ehrlich 424-78 Nouvel 424-80Winterstein 424-63 Neely 424-63 Freyermuth et al 424-63 Lachampt et al.424-63 X Factor 424-63 Factor et a1. 424-63 Lautfer 424-63 Larde et al424-78 X SHEP K. ROSE, Primary Examiner Y us. (:1. x11

